Tools for managing and scheduling meetings with students?

My advisor has been very busy and a lot of us hardly get quality time with him. he also acknowledges this and says it is usually very difficult to manage appointments and other commitments. He has lately been suffering from health problems, adding to crunch in time for all of us. Me and my advisor were discussing several ways to schedule and manage meetings with his students, preferably a web based tool so as to keep us informed in case schedule changes and also to let him remember which student met him and which didn't. (He has a lot of students with him including undergrads).

Google Calendar could be one such tool, but I am wondering how do people in academia schedule and manage meetings with students ?